A recent study by the Melman School of public health of Columbia University, the Robert Butler Columbia Center on aging and the University of Paris Dover PSL found that respondents with three or more children had a negative impact on their cognitive ability in later life compared with those with two children**
The data also show that this impact is greatest in northern Europe, where a higher fertility rate will reduce economic resources, but will not improve social resources. This is the first study to study the impact of high fertility on cognition in later life. So far, compared with other characteristics such as education or occupation, fertility as a possible predictor of cognition in later life has received little attention. The results were published in the Journal of demography.
Researchers say that understanding the factors that help to optimize cognition in later life is crucial to ensure successful ageing at the individual and social levels, especially in Europe, where family size has shrunk and the population is rapidly aging. For individuals, cognitive health in old age is crucial to maintaining independence and social motivation and productivity in old age. For society, ensuring the cognitive health of the elderly population is essential to prolong working life and reduce medical costs and nursing needs.
The researchers examined data from the European health, ageing and Retirement Survey (share) to understand the impact of having three or more children on cognition in later life compared with two children. Share collected representative sample data of the elderly in 20 European countries and Israel, including Austria, Belgium, Croatia, the Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Italy, Luxembourg, the Netherlands, Poland, Portugal, Slovenia, Spain, Sweden and Switzerland. Participants must be at least 65 years old and have at least two biological children.
Based on the advanced econometric methods, causality can be separated from simple correlation. The evidence shows that the cognitive ability of children with three or more children is worse than that of two children in their later years. They also found that the effects were similar for both men and women. Having an extra child will often incur considerable economic costs, reduce family income and increase the possibility of falling below the poverty line, thus reducing the living standards of all family members, and may cause economic worries and uncertainties, which may lead to deterioration of cognitive ability.
Having children will bring pressure to people, affect health risk behaviors, and adversely affect the cognitive development of adults. Parents with more children may experience more stress, have less time to relax, and invest in cognitive stimulating leisure activities. This may mean that parents don't get enough sleep.